powerpc/dts/t4240rdb: remove interrupts property

Since the interrupt pin for RTC DS1374 is not connected
to the CPU on T4240RDB, remove the interrupt property
from the device tree.

This also fix the following warning for hwclock.util-linux:
$ hwclock.util-linux
hwclock.util-linux: select() to /dev/rtc0
to wait for clock tick timed out
Signed-off-by: Biwen Li <biwen.li@nxp.com>
Acked-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200527034228.23793-1-biwen.li@oss.nxp.com

arch/powerpc/boot/dts/fsl/t4240rdb.dts

@@ -144,7 +144,6 @@ eeprom@56 {
 			rtc@68 {
 				compatible = "dallas,ds1374";
 				reg = <0x68>;
-				interrupts = <0x1 0x1 0 0>;
 			};
 		};